Substantial numbers of functional dentritic cells (DC) can be generated from precursor cells in blood or bone marrow upon in vitro culture with appropriate combinations of cytokines. For the in vitro development of DC from human CD34+ progenitor cells the most efficient cytokine combination was found to be GM-CSF plus TNFxcex1 and SCF. The culture media used for growing functional DC from progenitor cells were not only supplemented with exogenous cytokines, however, but also with serum or plasma. This raised the question whether, in addition to the added cytokines, also as yet undefined serum components play a critical role in the in vitro DC development. TGF-xcex21, known to be present in serum and plasma samples, is such a component. In its presence, but not or only minimally in its absence can substantial numbers of DC be generated from CD34+ progenitor cells also under serum/plasma-free conditions.
The invention concerns a process for the production of DC under serum/plasma-free conditions in the presence of TGF-xcex21.